Electric food mixer



July 21, `1936. A. F. DoRMi-:YER

ELECTRIC FOOD MIXER Filed Deo. 23, 1929 5 Sheets-Sheet l July 21, 1936. A. F. DQRMEYER 2,048,183

` l ELECTRIC FOOD MIXER Filed Dec. 25, 1929 5 Sheets-Sheet 2 July 21', 1936. A. F. Dom/MEYER 2,048,183

I ELECTRIC FOOD MIXER Filed Dec. 23, 1929 5 Sheets-Sheet 3 JUIY'ZL 1936 A. F. DORMEYER 2,048,183

ELECTRIC FOOD MIXER Filed Dec.- 23, lze v5 sheets-sheet 4 LQ7 llllllllllllllllllillIINg5/37 s 1 llilllllllllllllllllillllllll|||l||||||ll||||||||| `Iuly 21, 1936. A. F. DORMEYER 2,048,183

ELECTRIC FOOD MIXER Patented July 21, 1936 UNITED STATES PATENT oFFlcF,

ELECTRIC FOOD DIIXER Albert F. Dormeyer, Chicago, Ill., assignor, by

mesne assignments, to Hamilton Beach Manufacturing Co., Racine, Wis., a corporation of WisconsinV Application December 23, 1929, Serial No. 416,027

10l Claims. (Cl. 259-131) The present invention relates to electric food mixers, and is particularly concerned with portable household food mixers adapted to be used in the preparation of all kinds of foods.

pact in construction, so that the device may be conveniently controlled and handled without physical effort, yet it includes a power source of' suflicient strength to perform all types of physical household labor, and self-contained While the preferred embodiment, which has controlling devices which make the portable ma- 5 been chosen to illustrate the invention, is a food chine adaptable to the many diierent speed remixer, the invention also includes a motor unit quirements for such labor. which is peculiarly adapted to be utilized for all Another object is the provision of a novel selfkinds of household appliances or power driven contained unit for household appliances, which -devices in the home or elsewhere. The present includes speed reduction devices yto permit the 10 electric motor unit is also adapted to be used electric unit to operate at its most eicient speed, with many other attachments, such as fruit juice and speed controlling means to make the power extractors, meat grinders, vegetable slicers, unit capable of use with all kinds of household cream whippers, fans, massaging devices, floor appliances having various speed requirements.

5 and furniture polishers, emery wheels, polishing Another object is the provision of an improved 15 wheels, etc., and the use described is to be reportable food mixer which is adapted to stand garded as exemplary of one of the many uses of by itself in a container or upon any supporting a portable power plant or motor unit which is surface during the mixing operation or at other universally applicable to household labor. times, in order to eliminate the necessity for 'I'he food mixing devices of the prior art have constant attention so that the operator may leave 20 not been provided with power units having sufthe mixer to secure other ingredients, or to give flcient range* or flexibility of power and speed attention to other `urgent matters, during the control for performing the different kinds of mixing operation. mixing or other labor required of such a device, Another object is the provision of an improved and consequently, the prior devices were not mixing unit winch does not include any other 25 adaptable to both high-speed and low-speed regearing or mechanism that should not be placed quirements. For example, the speed which is in water, thereby facilitating the cleaning of required for whipping cream or mixing light liqthe mixing elements without wetting any of the uids is vastly different from that required for mechanism.

mixing dough for bread, and the devices of the Another object is the provision of an improved 30 prior art could not perform either or both of guard which positively prevents any of a pluthese functions with the perfection or rapidity rality of paddles or beaters from striking the side which is desirable in a commercially successful of bowls or receptacles of any size,- thereby premachine, venting noisy operation or injury to the mixing Some effort has been made to adapt mixing unit or bowl, such as would result if the radially 35 devices to different kinds of work by the use of extending paddles could strike the wall of the alternative gear ratios, but only a very limited bowl, so that the mixer may be used with the number of speeds could be secured by such an most fragile bowls or bowls of any size. arrangement, and such devicesy are complicated, Another object is the provision of an improved lo noisy, unwieldly and incapable of satisfactory mixing unit structure, which has no food col- 40 performance. lecting recesses, or inaccessible or diicult places The prior devices have also been too heavy, to clean, so that the mixing elements may be and too large to be handled conveniently by readily cleaned with running water, by operating women, expensive, difcult to clean, and difficult the mixer in a bowl of water, or by simply removto operate or control. ing and washing the mixing unit separate from 45 One ofthe objects of the present invention the gearing or motor. is the elimination of the foregoing difficulties by Another object is the provision of an improved the provision of an improved food mixer having portable household appliance which is capable such a wide rangeof power and speed control of beating, mashing, mixing, whipping, pulveriz- ""0 as to be adaptable to practically all kinds of ing, or stirring wet or dry food products of every 50 household labor. T consistency from thin liquids to thick batters or Another object is the provision of a portable dry mixtures, with a variable speed control for food mixer of the class described, which is light every different power or speed requirement. in weight, relatively small in size, and com- Another object is the provision of an improved I paddle structure of the Dover type which is 55 peculiarly -simple and sturdy, easy tomaintain in clean,condition, and capable of economical manufacture and assembly.

Another object is the provision of a portable electric food mixer, which may be safely left connected for convenient use and control by means of a self-contained switch located in the motor casing, andthe paddles of which may be safely cleaned byrunning water while the motor is in operation.

Another object is the provision of an improved portable food mixer having a detachable mixing unit, which is sec'uredto the motor unit by a ilrm .and positive, yet quickly detachable, connecting device, so that the mixer unit may be safely and securely connected to the motor unit-to suPDOrt the same, but the mixing unit may be readily removed for cleaning, and the motor unit may y be applied to many other types of appliances.

Other objects and advantages of the invention will be apparent from the following description and from the accompanying drawings, in which similar characters of reference indicate similar parts throughout the several views.

Referring to the drawings, of which there are ve sheets;

Fig. 1 is an elevational view of the portable food mixer in erect and operative position in :a round bowl;

Fig. 2 is a full size elevational view of the agitator unit, partially broken away to show the 'A structure;

Fig. 3 isa diagrammatic sectional view taken on the plane of the line 3-3 of Fig. 2, showing the relation of the beaters and guard with respect to a flat walled receptacle;

Fig. 4 is a. detail sectional view taken on the plane of `the line 4-4 of Fig. 2, looking in the direction of the arrows;` l

Fig. 5 is a vertical sectional view taken on a plane determined by theaxesof the drive shafts,-

` direction of the arrows;

Fig. 9 is a vertical sectional view taken on the plane of the line 9-9 through the casing with the internal mechanism in elevation;

Fig. 10 is a. horizontal sectional view taken on the plane of the line |0--i0 through the motor unit, showing a plan view of the rheostat;

Fig. 11 is a vertical section through the casing alone taken on the plane of the line ii-I I 4of Fig. 9, with the mechanism removed from the casing;

` Fig. 12 is a fragmentary vertical sectional view taken on the plane of the line I2|2 of Fig. 8.

, Referring to Figs. 1 to 3, the present electricI food mixer, which is indicated in its entirety by the numeral20, preferably consists of a separate agitator unit 2i and a separate motor unit 22. Both of these parts comprise-unitary articles of manufacture, and the motor unit in particular is capable of use as a power plant with many different types of household appliances, of which the agitator unit or agitator attachment is one example. ,Y

The present food mixer is preferably made ingredients, as for instance, when another egg portable in order to widen its field of utility and adapt the food mixer for use in mixing food in all kinds of 'household utensils. While the present device is extremely sturdy and capable of long and emcient service, all excess weight has been 5 eliminated by the provision of an improved structure,rsov that the complete mixer is so light that very little effort is required on the part of the user.

AOne of the primary purposes of the food mixer being to save physical effort on the part of the user, some of the objects of the present invention would be defeated if excessive physical effort were required for handling the mixer, and the present portable device possesses an adaptability 15 and iiexibility in its application to various house- Vhold labors, which was not present in the devices of the prior art.

In order to eliminate the necessity for constant attention to the fod mixer when the device is in 20` operation or between successive operations when the'agitator unit may be covered with the batter, or other ingredients which it is mixing, the mixer is preferably provided with a stable supporting member, such as the agitator unit 2|, which is' 25 adapted to support the complete device in erect position under a large variety of different conditions, one of which is illustrated in Fig. 1.

For this purpose, it is also desirable that the motor unit 22 be provided with inherent balance and connected to the agitator unit 2| symmetrically so that the mixer is not overbalanced upon any side.

It is thus unnecessary to hold the food mixer in erect position as in Fig. l, and under ordinary conditions, the food mixer is adapted to maintain such position without tipping while the motor and y agitator unit are operating at full speed. The user may thus leave the mixer to secure additional is desired in the mixing of cake batter, or the 40 device may be left during the mixing operation to attend to other urgent duties, such as the observation of other food in the .process of cooking.

This inherent capability of standing alone is also of material advantage whenever the mixer has been stopped since it will be evident that it is undesirable to remove the mixer from the batter and wash it until the mixing has been completed, and it is also undesirable to permit the mixer to lie on its4 side with the agitator above the bowl, because the batter might then run down the agitator shafts, which are tilted downward in inverted position. Y

It will be noted, therefore, that the inherent stability of the food mixer is a very important advantage ,which is not present in the devices of the prior art, and which contributes in a large measure to the elimination of the inconvenient K operating characteristics of the prior devices. eo

The agitator unit is shown in elevation in the full size drawing, Fig. 2, and this unit preferably includes a supporting member or plate 23, a guard indicated in its entirety bythe numeral 39, and vone or more agitators 25. The supporting plate 23 05 forms a part of a positive and safe, yet quickly detachable, connection between the agitator unit 2i and motor unit 22, and for this purpose, a supporting plate 23 is provided with a socket 24 y adapted to receive complementary male members 70 or lugs 25 carried by motor unit 22.

The plate 23 may be conveniently formed of a sheet metal stamping'of substantially rectangular i form, having a bottom 26 and upwardly extending side ilanges 21, 28, 29 and 30, forming the socket 24. In the present embodiment, the plate 23 ls also formed with a centrally located stamped depression 3|, providing additional space Within the socket 24 for receiving and enclosing the bushings 32, 33, and other mechanism for rotatably supportingthe drive shafts 34, 35. The stamped depression 3| is provided with a pair of apertures 36, 31 for receiving the drive shafts 34, 35. The bottom 26 of the plate 23 is provided with a plurality of apertures 36 used `in securing the guard 39 to the supporting plate 23.

. Referring to Fig. 9, it will be observed that the casing 4l) of the motor unit 22 is provided at lts bottom 4I with a projecting body 42 for the purpose of securing the supporting plate 23 of the guard. 'I'he body 42 is preferably complementary in cross-section t` the socket 24 formed in plate 23, and in the present embodiment, both' the socket 24 and body 42 are made rectangular in shape.

Iiism associated with the drive shafts 34 and 35.

In order to maintain these parts in assembled relation, the lugs 25 are provided with transverse bores 43, 44 for receiving threaded members 45, such as screw bolts having enlarged bodies 4 adjacent the knurled head '41.

'Ihe outer end of the screw bolts 45 may be provided with points 43 of reduced diameter to improve the appearance, `decrease the weight, and

cooperate with relatively small apertures 49 formed in the flange 29 of supporting plate 23. The opposite flange 36 is provided with enlarged apertures 56 adapted to register with the bore 43 and receive the enlarged cylindrical body 46 and screw bolt 45, but the apertures 50 are preferably formed with slots 5l of sufficient width to pass the screw bolt 45 when the screw bolt has been moved out to the position of the right-hand bolt in Fig. 6.

' The bore 44 ofthe lug 25, which is located adjacent the outer end of bolt 45, is threaded, and the outer end 52 of bolt 45 is threaded to be received in bore 44. The bore 43 is made of greater diameter than bore 44 in order to pass the threads 'on the end 52 of bolt 45 so that the bolts 45 may be inserted from lthe top in Fig. 6.

It will thus be observed that when both the bolts 45 are withdrawn to the position shown with respect to the right-hand bolt of Fig. 6, the ends 48 of the bolts 45 are withdrawn from the apertures 49, and the enlarged portions 46 of the bolts 45 are withdrawn from the apertures 50.

Since the slot 5l will pass the body of the bolt 45, the supporting plate 23 .may then be slid oli the body 42 and lugs 25, and the agitator unit may be readily removed by merely giving the bolts 45 a few turns and pulling the agitator unit away fromA tween the shoulders 59 loose parts which may be lost when the motor unit i is disconnected from the 'agitator unit, because the bolts are intended to be left in the position of the right-hand bolt in Fig. 6, and it is not necessary or desirable to remove the bolts entirely.

The guard 39 preferably includes a plurality of vertically extending frame members 53, 54, 55, 56, y

carried by the supporting plate 23 and formed with a plurality of feet 51 for engaging the bottom of a bowl or other support. The frame members 53-56 are preferably formed of relatively stiff strips of metal, such as steel, and the frame member 55 may consist of a continuation of the frame member 53. Each of the frame members 53-56 is provided with an end portion 58 of reduced width at its upper end, forming shoulders 59, and the end portions 58 are adapted to be received in the apertures 38 of supporting plate A23 so that the guard 39 may be secured to the sup: porting plate by riveting over the ends as at 60 The supporting plate 23 is thus confined beand the rivc on each frame member of guard 39. tihenpdressg cnt agitator unit preferably includes a pair of separate beaters or agitators 6i, arranged side by side with interengaging beater members 62 63 and the framefmembers 53, 55 are preferably lo: cated in substantially the same plane with the drive shafts 34, 35 to guard the outermost parts of the beater members 62, 63. Thus the frame member 53 is provided with a relatively straight body portion which extends longitudinally in the direction of the drive shafts 34, 35, but the frame member 53 is bent outward at 64, and provided with a curved guard portion 65, which may conform somewhat to the shape of the beater members 62, 63. The curved portion 65 of frame member 53 terminates at the bottom in a downwardly curved portion which has been called `a foot 51, after which the frame member is bent upward at 66 and it extends substantially horizontally at 61. The opposite frame member 55 may be identical in shape, the two frame members being joined at the horizontal portion 61 and formed of a single integral strip of metal.

Referring to Fig. 1, the frame members 54, 56 also include longitudinally extending body portons= which are secured to the supporting plate 23 in the manner just described. Since these frame members are located transversely to the plane of the drive shafts 34, 35, the beater members 62, 63 do not project s o far in this direction, and each of the frame members 54, 55 may be bent outward at 68, and curved downward at 69, terminating in a downwardly curved portion or foot 51, and joined by an upwardly curved portion 10, which engages the horizontal portion 61 of the frame members 53, 55.

v The portions 61, 16 of the guard are preferably iirmly secured together, as for instance, by a rivet 1I, thereby holding these parts in fixed relation at the bottom, and accordingly increasing the rigidity of the complete guard. Since the guard 39 is provided with a plurality of spaced 75 feet s1. it is peculmiy adapted to stand .upright in bowls of all kinds, particularly bowls 12 of i, the type illustrated in Fig. 1, having afprojectlon 13 centrally located in the bottom of the bowl.

. guard and the bowl. The downwardly curved portions 51 on the metal strip, which form the guard 39, are also peculiarly adapted to cam away any nuts, raisins, or other particles of foodwhich might otherwise remain beneath a plane supporting surface, and the curved feet 51 have been found very effective to automatically locate themselves in a stableposition upon the bottom of a bowl full of food ingredients.

The beating elements 6I are preferably identical in shape and construction, and consequently, it is only necessary to describe one of these beating elements in detail. Each beating element 6I preferably consists of a tubular shaft 14, 'the upper endof which has been deformed to provide anon-circular portion 15, which forms a socket of similar shape for receiving the noncircular end of a drive shaft 34 or 35. The lower end of the tubular shaft 14 supports the beating elements 62, 63, which preferably consist of a;`

dles 62, 63 are made, are preferably considerably wider than the interior of the shaft 14, and consequently, the edges of the paddles 62, 63 are tapered as at 18 adjacent the upwardly bent ends 16, 11, and formed so that when the ends 16,

11 are located within the. tube,14, the taperedA edges 18 fit against each other and preventrelative rotation of one paddle with respect to the other.

The outwardly extending ends 16, 11. of the paddle 63 are similar in form to the ends on the paddle 62, and all of these end portions are preferably reduced in width, so that they are adapted to form a composite tubular member of a size adapted to be received within the tube 14. The paddles may thus be secured to the shaft 14A by means of a driven member 19 of substantially cylindrical form, having a head` 30 and a tapered end 8i for camming the ends 16, 11 into proper position during the driving operation.

The driven member 19 secures the paddles to the shaft 14 with the edges of the respective strips in position to reinforce and support each other, and the stud 19 is maintained in its p0- sition by frictional engagement with the end yportions 16, l1, and by the tension of the tube 14 about the stud 19.

yThe paddles 62, 63 are each provided with a pivotal connection to the horizontal portion 61 of the guard 39, and the paddles 62, 63 of each beater element are preferably each formed with Y ing the lower end of the beater element6l, and

for permanently maintaining the assembly of vbeater elements and guard. Spacing members 93 are preferably interposed between the paddles and head of rivet 82 land between the paddles and the guard. ,The upper end 15 of each tubular shaft 14 is rotatably supported in onefof the apertures 36, 31 voi? the supporting plate 23, so that the agitators are constantly maintained in 5 power position with the guard.

Referring to Fig. 3, this is a diagrammatic illustration of one example of the relation between the guard 39 and the agitators 6l for preventing the paddle from hitting the side of the mixing l0 bowl or receptacle. In order to prevent the clatter which would otherwise result from the periodic striking of the bowl by the paddles 62, 63, the outwardly curved portions 65, 69 of the guard 39 are so located withrespect to the paddles 62, l5 63 that the paddles are spaced from the wall of the bowl to prevent engagement between the paddles and bowl.

Thus in Flg.3, at the right-hand side, it will be observed that the portions 65, 69 of the guard 20 project' beyond the .paddle 63, so that, a line drawn between the points 65, 69 is located outside of paddle 63. The guard illustrated in Fig.

'3 is peculiarlyradapted to prevent interference between the paddles and the wall of a vessel hav- 25 ing plane sides, but since the ordinary mixing vessels are usuallyround bowls, some embodiments of the invention need not have the guard portions 65, 69 project so far in a lateral direction.

It will be evident from Fig. 3 .that in order to 30 prevent interference between the paddles and the wall of a curved bowl, the paddle 63, for example, need only` be located within a curved wall 12 when the outer portions 65 and69 of the guard engage the wall. 35

In many embodiments of the invention, it will be suiiicient, therefore', to adapt the guard to prevent interference between the paddle and bowls of ordinary size, and it will not be necessary to extend the guard suiciently for use with ilat sided vessels as taught by the present description. i

It will thus be observed that the present agitator unit is peculiarly adapted to maintain itselfin erect position in the mixing bowl, and also to support the motor unit in the same position when the motor is still or while the motor is operating. The guard ispeculiarly adapted toprevent interference between the paddles and bowl so that the paddles cannot strike the side of the bowl, and it is possible to use the present mixer with the most fragile bowl without possibility of the bowl being broken by the paddle, and without the clattering noise, which would inevitably result from the paddles of the prior art.

The tubular beater shafts and paddle construction are also peculiarly adapted tobe very easily cleaned, because there are no recesses which retain particles of food, nor are there any difllcult or inaccessible places to clean as distinguished from the devices of thelprior art, in which the paddles invariably consist of elongated metal strips instead of tubular shafts.

The entire agitator unit may be readily re- 65 moved from the motor unit without any mechanism such as gears or other parts that might be damaged by washing, and the agitator unit may be washed in the ordinary way of washing dishes,' or by running the food mixer with the agitator unit inl a bowl of cleansing fluid, such as soap and water. All of the metal parts of the agitator unit are preferably` plated with corrosion resisting metal, such as chromium, and the casing 40 for the motor Ais preferably formed of a light parts carried by a standard or aluminum alloy, capable of receiving a `nnish which is similar in appearance.

Referring to Figs. '7 to 12, I ,shall now describe in detail the features of an electric motor unit which ispeculiarly adapted to provide a source of power for the agitator 2| for performing all ,kinds of mixing, beating or pulverizing operations. 'Ihe electric motor unit 22 preferably consists of a unitary motor casing 40, which encloses and protects the motor 86, a speed control device 8,1, and a speed reduction; device 80. The exact shape of the casing 40 does not affect the merits of theinvention, except that it is highly desirable that the arrangement be light and compact, and a very emcient, sturdy and powerful motor unit is provided by the specific arrangement illustrated.

The motor unit is illustrated in'full size in the figures justmentioned, and the entire mixer is so light that it may be handled without appreciable physical effort, yet it is capablerof performing many new functions besides all of the results which have been accomplished by the large heavy and complicated mixing `devices of Ainwardly adjacent thebottom of the casinig.

The transversely extending grooves 95 formed in the side Walls `93, 94 enhance the ornamental appearance of the casing, and may also be em- Iployed as guides for receiving complementary other support (not shown).

The casing 40 is closed by means of a cover of which the front wall 90 forms a part, the cover |04 also including a laterally extending flange |05, about the border of the front wall 90, the

flange |05 being adapted to register with the top,l

bottom and side walls of casing 40. The flange |05 is preferably recessed at |06, forming a relatively thin aligning flange |01, adapted to be received within the walls of casing 40 to align the 'in lugs |l2 carried within casing 40 by the walls thereof.

Casing 40 is preferably provided with a pair of handles 96, one located on each of the side walls of the casing, and the handles 96 are preferably formed of electrical insulating material, such as a molded phenolic condensation product, called bakelite. Handles 96 may be very firmly Hsecured to the casing 40 by providing the upper end .91 of the handle with a transverse groove 98 which is adapted to receive the upper corner of the casing 40, so that the handle engages both the side wall 94 and the top wall 89.

The handle may be provided with threaded bores 99, |00, and securedto the casing by screw bolts |01, |02, which pass through the walls of casing 40, and the upper screw bolt is preferably provided with a frusto -conical nut- |03 adapted to be received in the corner in the interior of the casing, between the top wall 89 and side wall 94. The handle being drawn into firm engagement with both 'the top wall and the side wall by the bolt |0|, and being also secured by the bolt |02, the handles are adapted to be firmly secured to the casing with a minimum amount of labor.

'I'he handles 96 are also a great convenience for the housewife in the manipulation of the mixer since either hand may be used for steadying the mixer in pulverizing operations or other operations which require steadying, and the other hand may be used for controlling the speed of the motor. v

'Ihe support or control of the device may be readily shifted from one hand to the other to enable the operator to reach for ingredients on either side, and if necessary both handles may be grasped in such manner that the motor unit may be held very firmly and a considerable amount of force brought to bear upon the work where the motor is used for other operations than food mixing.

The speed reduction mechanism 88 also forms a unitary part of the motor unit, being enclosed f in the casing 40, and permanently secured thereto, so that no gears or other mechanism need be attached to the agitator unit, and the operator needhave no hesltancy aboutplacing the agitator unit in the water for washing on account gears or other mechanism such as are used in the devices of the prior art.

Since the present agitator unit includes `a pair of beater elements, the motor unit has been provided with a pair ofidrive shafts 34, 35, but it should beunderstood that it is not necessary to utilize both of the drive shafts when themotor is employed with other appliances. The bottom wall 4| of casing 40 may be provided with a pair of bores ||3, for receiving bushings 32, 33, whichform bearings for shafts 34, 35.

Referring to Fig. 5, it will be observed that each of the bushings 32, 33 has an axial bore I I4 forming the bearing, an annular flange ||5 engaging the inside of the bottom wall 4|, and a threaded portion ||6 for engagement with an internally threaded cap Ill.

The bearing structure of each of the drive shafts is substantially identical, and consequently, only one of these structures need be described in detail.' The drive shaft 34 is iixedly secured at its upper end to a combined bevel and spur gear ||8, while the drive shaft 35 is secured in a similar manner to a spur gear I9, which is adapted to mesh with the teeth on the spur gear I8. All of the gears included in the present device may be made of cast metal and secured to the drive shafts by casting the gear about one end of the shaft, or the gears may be made out of ber for the purpose of giving a more silent operation, in which case, the gears may be secured to the shaft by pins or other fastening means.

For the purpose of assembly, each of the drive shafts 34, 35, its bearing and gear, preferably consist of a unitary assembly, which is held together by the provision of an annular groove |20 formed in the shaft just below bushings 32, 33, and provided with a split ring |2| to prevent removal of the shaft from its bearing. Washers may be placed on either side of the split ring and an absorbent packing |22 carried in the cap is adapted to prevent leakage of oil out of the bore I bearings 32, 33 may be provided withA a supply of -lubricant by a piece of absorbent felt |26, which is placed on the bottom of the casing 40 about the annular flanges II5 of the bearing, and secured in place by the plates |24. l

In order to provide a self-locating drive connectionbetween the electric` motor unit and the two-element agitator unit, one of the drive shafts, such as shaft 34, is made substantially longer than the other shaft 35, so that the shaft 34 projects below shaft 35. Both of the shafts have non-circular ends, the non-circular forma;- tionsextending upward to a point within the bearing caps IIl on each shaft, and the complementary non-circular sockets 15 on tubular shafts 14 may be of suiicient length to receive either of the shafts, -in order to secure standardization of parts.

Since the drive shafts 34, 35 are located with their gears H8, I I9 enmeshed in such relative position that when the motor unit is assembled with the agitator unit, as shown in Fig. 1, the paddles 62 or 63 on one beater element 6| are located midway between the paddles on theother beater element in suchmanner that the paddles rotate 'between each other without interference. The paddles themselves are adapted to approximate vthis position even when the agitator unit is removed as in Fig. 2, on account of the interengage- 'ment with the paddles 62, 63, and the shafts 34, 35 are preferably provided with tapered portions |21 at their lower ends for engagement with the upper ends of the tubular shafts 14, so-that the tapered surfaces |21 are adapted to automatically cam and rotate the tubularshafts 14 imtll they reach the proper rotative position for engaging the non-circular ends |28 of shafts 34, 35. AsA

previously stated, when the tubular members 14 are actually engaged upon the squared end |28 of the drive shafts, the paddles 62. 63 are denitely placed with respect to each other, so that the pad-4 dles on one shaft rotate between the paddles on the other shaft without touching.

Since the agitator unit is adapted to be slid upon the lower part of the motor unit in securing these parts together, some difficulty might be encountered in aligning the mechanism in this sliding operation were it not for the fact that a selflocating means is provided in thev form of the elongated shaft 34, which operates as follows.

When the supporting plate 23 approaches the bottom of the motor unit, it is a relatively easy matter to find one of the sockets in the non-circular end of one shaft 14 byv means of the elongated shaft 34. The shape of the supporting I plate itself with a centrally located depression 3|,

aids in directing the drive shaft 34 to the proper position, and the sha-ft 34 slides easily into its tubular member 14. With the parts in this position and the agitator unit only connected with one elongated shaft, the agitator unit may be rotated on its axis with respect to the motor unit until the side flanges 38 become aligned with lugs 25, after which the supporting plate 23 vmay be pushed up into the position of Fig. 5, the shaft 35 being received in its tubular member 14.

'I'his capability of rst locating one elongated shaft is of further assistance in quickly connecting the agitator unit to the motor'unit, although the squared ends of the beaters 6| may not be in quite the proper position to receive the squared ends of shaft 34. A slight rotation of the beater unit will bring the beater in position to engage the squared end of the shaft, after which the agitator unit may be rotated back to the proper n bearings |43 at each end, which are capable of a position for sliding the cupped plate 23 about the lugs 25 and body 42. The second tubular shaft is then located with sufficient accuracy by the interengagement of its paddles with the paddles of the shaft already located, and the tapered ends |21 of 5 the drive shafts complete the connecting operation without dimculty.

It will thus be observed that the present connection between the beater unit and motor unit with a pair of shafts may be very readily and 10 easily affected by the mechanism provided, and the agitator unit is quickly attachable', as well as quickly detachable. u

The speed reduction mechanism 88 also includes a pinion |23 carried'by the armature shaft I30a l5 spur gear |3| rotatably mounted upon a shaft I 32, the spur gear being also provided with a bevel pinion |33 fixed to'rotate with gear I3 I. The rear wall 3| of casing 40 may be provided with an internally projecting lug |34, having a bore |35 20 which is in alignment with a bore |36 located in a similar lug |31 carried by cover |04. Shaft |32 may have a knurled end |38, and may be provided with a thrust bearing consisting of a collar '|39 pinned to shaft |32. The knurled end |38 may 25 have a drive fit in the bore |35, and the combined spur gear and bevelA pinion |3I, |33, is rotatably mounted on the shaft |32 between collar |39 and lug |31 with suitable washers |40 to facilitate proper meshing of the bevel gears. The drive shafts 34, 35 are thus adapted to be rotated by the motor armature I4| through the following train of gears; pinion |23 rotates spu'r` gear |3I, which carries bevel pinion |33, bevel pinion |33 rotates` bevel gear |42 which carries spur gear I I8, meshing with spur gear IIS, and the spur gears I|8, '|I9 being of the same size, both shafts 34, 35 rotate at the same speed.

The motor 86 ymay thus be operated at a relacient operating speed of the motor. In the embodiment illustrated, the speed reduction gear is adapted to reduce the speed in the-ratio of nine to one, and with the speed control, which is described in full hereinafter, the present device is adapted to be operated at speeds of several hundred revolutions per minute to over 1500 revolutions per minute.

' 'I'he motor shaft I 30 is preferably provided with 60 limited universal movement to automatically align the bearings |43 with shaft |30 when the cover |04 is placed on the casing 40. Eachof these bearings may be substantially identical in form, and consequently, only one of the bearings 5 is described in detail.

For instance, the cover |04 isformed with a substantially cylindrical socket 92 having an annular groove |44 located ynear the mouth of the socket. A stamped annular sheet metal member 60 |45, forming a small portion of `a sphere, is adapted to :dt within the socket 32 with an outwardly extending ange |46 in groove |44. The bearing |43 comprises a sleeve |43 of bearing metal, which is provided with an annular ange 65 |41 at its outer end, and which is xedlysecured with a ball-shaped metal member |48. The ball |48 flts within the spherical cup |45 andthe flange |41 may support a felt packing |49 adjacent an oil conduit |50.

All ofthe foregoing parts' are secured in the, socket 32 by an annular plate I5I, which is se-` cured in place by screw bolts |52, and which is provided with ,an annular inwardly sloping ange |53 for engaging ball |48. Any number of wash- 75 ers |54 may be interposed between pinion I 29 and bearing |43. and the plate is preferably provided with a stamped depression' for engaging in a slot |55 to permit universal movement of ball |48, but to prevent rotation of the ball. The plate |5| is also preferably formed with slots |58 extending into said plate from its outeredge about each screw bolt |52, so that the plate is secured in place by screws passing through resilient tongues formed on plate |5|. ,Y

Referring to Figs. 9 and 11, it wuibe observed` that the side walls 93, 94 of motor casing 40 are provided with inwardly projecting and transversely extending ribs or formations |51, the lugs on each wall being provided with an inner cylindrical surface |58 which is complementary in shape to the outer surface of the motor field core |59.

At the points |60 on each rib |51, a definite shoulder is formed against which the motor field core |59 rests and the field core may be secured in place' by screw bolts and washers |6| threaded in bores |62 in the end of lugs or ribs |51. The motor field core |59 is preferably constructed of a multiplicity of laminations of soft iron, or similar material having high magnetic properties, each lamination being a substantially annular' metal plate formed with two inwardly projecting pole pieces |63, |64, the lpole pieces being widened at their ends to form grooves |65 for receiving the iield windings |66, |61. Each of the field windings |66 consists of a coil of a plurality of turns of relatively heavy insulated wire adaptedvto carry full load current, since the present device is preferably provided with a series motor.

The armature |44 alsocomprises a plurality of laxninations of soft iron, or other magnetic material, all of which are provided with registering recesses |14 and slots |15 leading to the outside of the armature. The elongated recesses |14 are adapted to receive the armature coils |16, consisting of a plurality of turns of insulated copper wire, the wire being retained in recesses |14 by strips of insulation` |16 slid endwise into recesses |14 to close the slots |15. The ends of the respective armature coils |16 are connected to the insulated segments |11 of a commutator 18, xedly supported on shaft |30, and the commutator |18 ismadapted to be engaged by the oppositely disposed brushes |69, |12.

Any compact form of series winding may be used for the armature coils |16, and wire provided with lacquer insulation is preferably employed.

to reduce the size of the armature and increase it's eiiiciency. The shaft |30 also supports a fan |19, consisting of a sheet metal plate having a plurality of radially extending armatures |80 with inwardly turned blades |8|.

VThe casing 40 and cover |04 are also provided with a plurality of ventilation openings |82 located about each endV of the shaft in the iront and rear walls, and these walls may also he provided with ventilation openings |83 adjacent the top to provide ventilation for the rheostat 81. y

The side walls 93, 94 are provided with bore |84 at points diagrammatically opposite each other with respect to the commutator |18, and the bores |84 support bakelite tubes |85 for insulating the brushes |69, |12. The bakelite tubes |85 are each molded about a sheet metal tube |86, having a crimped end |81 to provide anchoring formations, and themetal sleeves are provided with annular anges |88 at the inner end, the sleeves |86 projecting suiiciently from the insulating bushings las to form a connec- The brushes |69, |12 may `consist of carbon each formed with a small head |90, about which one end of a helical spring |9| may be engaged. The insulating bushings |85 are provided with internal threads,- |92, and an insulating screw plug |93 is threaded in the end of each bushing |85 to compress the` helical springs |9| and maintain the brushes |69, |12 in engagement with commutator |18. The connectors |89- are peculiarly adapted to receive the resilient clamping fingers |94 of connectors carried by conductors leading from the iield coils |66, |61.

The speed control device 81 preferably consists of a series rheostat, including a plurality of resistance windings |95, the various turns of which may be successively connected in series with the armature and field circuit of motor 86 by a movable switch arm |96.

Referring to Fig. 11, it will be observed that the side walls 93 and 94 are each provided with transversely extending ribs |91 adjacent the top, the ribs |91 having longitudinal slots |99 for slidably receiving the edges |99 of an insulating support 200 for rheostat 81.

The insulating support 200 may consist of a molded porcelain member or plate of substantially rectangular form preferably provided with upwardly projecting and downwardly projectretained in its guides |98 by engagement of the anges |01 of the cover with the edges |99 of the porcelain.

The porcelain supporting plate 200 of rheostat 81 is provided' with a plurality of apertures 202, located in two series along two concentric arcs, and the apertures 200 provide means for securing a plurality of rheostat contacts 203, each of which consists of a sheet metal cup or head, having a pair of downwardly extending prongs 284 for clamping the contact to the porcelain.

'I'he resistance windings |95 `consist of a plurality of spaced turns of resistance wire, and the contact bodies 204 form contact with the turns 95 by the engagement of the lower sides 205 of contacts 203 with adjacent turns of the coils |95.

The` last contact |13 is preferably provided with a downwardly extending metal iiange 206 provided with a screw 201, forming a connector for connection with one of the supply conductors. The porcelain body 200 is also provided with an upwardly projecting lug 208 for supporting an elongated metal strip |1| forming one of the contacts of the rheostat 81.

The elongated metal strip |1| has one end supported in a recess 209 formed in a ange 20|, and the opposite end is bent' downward and passes through an aperture in the porcelain body 200, to form a connector 2|0, provided with a screw 2|I. The metal strip ,|1| is also provided with a punched tongue 2|2, which is bent downward through another aperture in porcelain body 200 and bent into engagement with the bottom of the porcelain body to secure the elongated contact strip |1| on the porcelain body 200. l

The upper wall 89 of casing 40 is provided with a centrally located bore 2|3 for receiving an insulating thumb piece 2|4, and the thumb piece 2|4 is provided with a portion 2|5 of reduced diameter, forming a shoulder 2|6 for engaging the top of the casing. The thumb piece 2|4 is preferably provided with a screw bolt 2|1, having its head molded in the thumb piece 2M, and having a attened lower portion for :non-- rotatably supporting a movable contact |96. An insulating washer 2|8 is interposed between the movable contact |96 and the casing wall 89, and the contact |96 is secured onbolt 2|1 by a nut Referring to Fig. 7', it will be observed that one end of contact arm I 96 is provided witha contact rivet 220, having a curvedface for slidably engaging the contact bodies ,203, |13, and the opposite end 22|` of contact arm |96 is adapted to engage the elongated strip contact |1|. body 200 is alsofprovided4 at one side with a porcelain projection 222, simulating the shape of a contact 203 and adapted to serve as a dead contact for the off-position of the switch arm |96.

The nameplate 223 may be interposed between the thumbpiece 2|4 and casing wall 89, and the wall or nameplate is preferably provided with in.- dicia, such as on or off with appropriate arrows, or a scale for indicating the various posiy tions of switch arm |96.

One end of coil |66 is connected to one of the wires leading to the supply conductors |68, while the other end of coil. |66 is connected to one of a pair of brushes |69. One end of coil |61 is connected by conductor |10 to the elongated fixed contact |1| of the rheostat 81, and the other end of coil |61 is connected by a conductor to brush |12. The last contact |13 of a series) of rheostat contacts is the other terminal of the rheostat Since one end of the motor circuit is connected by conductor |10 to one end of the elongated fixed contact |1|, the movablecontact |96, which en-y gages the strip |1|, is adapted to connect in the circuit various turns of the resistance wire |95. depending upon engagement of the contact 220 with the various rheostat buttons 203. When the contact 220 is in engagement with the upper rheostat contact 203 in Fig. 10, the entire set of resistance windings |95 is inl circuit, so that the second position of the thumb piece 2|||v provides the slowest rate of speed. When the contact 220 -is moved to the position vto engage the second rheostat contact 203A, one-fourth of the lresistance wire |95 is cut out, and three-fourths of. the rheostat resistance is in circuit, and so forth.

y When the contact 220 has reached the last rheostat contact |13, all of the resistance is cut out,

and the motor operates at its highest speed.

l The mechanical operation of the foregoing food mixer will be evident from the foregoing description and statement of the functions of the variousparts.` However, the present combination of series rheostat control, series motor and speed reduction device are particularly effective for the purpose of providing a food mixer or household power unit having a vwide range of adaptability and speed'control for various purposes. I

'I 'he series commutator motor is capable of op eration on either direct or alternating currentvat ordinary lighting circuit voltages and the characteristics ofthe motor are such that the motorv is equally adaptable to mashing potatoes or mixatively thick batter.

The porcelain ing heavy batter at slow speeds as it is to the high speed mixing of relatively thin` liquids or material to be whipped.

When the mixer is used in a relatively thick batter, the increased resistance tends to decrease, 5 the speed of the motor, which decreases the counter-electromotive force generated in the armature, and the motor takes an increased current, providing the necessary power for mixing the rel- While the motor has the inherent capability of decreasing its speed considerably under conditions of such an increased load, the best operation is secured by the use of the series rheostat, which further decreases the speed of the motor and 15 gives a relatively powerful mixing device/which operates at a very low speed when mixing heavy or thick batters.

Since the rheostat is in series with the motor, when an increased load'is placed upon the series 20 motor having 'a series rheostat, the increased current makes a larger potential drop across the rheostat, and consequently, reduces the eifective voltage on the motor. This reduction in the vol'tage impressed on the motor gives a proportional reduction in speed which also gives a decreased counter-electromotive force and further results in increased current with increased power and slower speed. v'

The various steps provided on the rheostat are thus adapted to provide-a milch wider range of speed control than would be. provided by'a rheostat with any other arrangement, and the present food mixer has been found to be peculiarly effective and adaptable to all kinds of mixing, performing many operations lwhich have heretofore not been possible with any motor driven food mixer.

YIt has already been pointed out that the motor unit is compact, light, capable of use with all kinds of motor driven household appliances and economical in its manufacture and assembly.

The agitator unit is also peculiarly adapted to 'be used for mixing at all rates of speed, and the agitator is capable of extremely highrates of speed without any splashing of the liquid or other ingredients. The mixer may thus be used in `bowls which are relatively full without splashing upon the clothes' of the wearer and without th loss of any of the material. Oneiof the most important features is the provision of a portable food mixer, which is capable of standing alone while in operation orwhile the 'motor is shut oif, and the usefulness of the present device is greatly increased by the provision of such a balanced motor structure having a stable supporting device.

While I have illustratedv a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, what I claim is new and desire to secure by Letters Patent of the United States, is: ,Y

1. An improved agitator for food mixers, comprising a tubular shaft, apair of metal bands bent to .circular form and having outwardly projecting ends 'extending into said shaft, and a metal'member driven between said ends and the interior wall of said shaft to-secure said shaft and bands together.

2. An improved agitator for food mixers. comprising a tubular shaftfa pair of metal bands bent to circular form and having outwardly projecting ends, and a metal member driven between said ends and the interior wall of said shaft to secure said shaft and bands together, the ends of said bands having edges shaped to engage each other adjacent said shaft.

3. In a portable food mixer, the combination of a motor casing having a series commutator motor in said casing, with a control rheostat 1ocated in said motor casing and connected in series with the circuit of said series motor, a pair of drive shafts rotatably mounted in said motor casing, gears connecting-said drive shafts and said motor in said motor casing, and a pair of beaters removably mounted on said drive shafts, comprising elongated tubes fitting on said shafts and circular sheet metal strips carried by said tubes.

4. In a portable food mixer, the combination of a motor casing having a series commutator.

motor in said casing, with a control rheostat lo-V cated in said motor casing and connected in series with the circuit of said series motor, a pair of drive shafts rotatably mounted in said motor casing, gears connecting said drive shafts and said motor in said motor casing, a pair of beaters removably mounted on said drive shafts, comprising elongated tubes fitting on said shafts and circular sheet metal strips carried by said tubes, and a removable guard member, comprising a base plate and guard strips located to prevent contact between said beaters and a receptacle.

5. A portable food mixer, comprising a motor casing formed with grooves on opposite sides, a rheostat base plate slidably mounted in said grooves, a rheostat control member movably mounted in said motor casing wall, a series electric motor enclosed in said casing and connected in series with said rheostat, a drive shaft rotatably mounted in said casing, a detachable guard member carried by said motor casing, and a beater having one end rotatablyk mounted on said guard and the other end on said drive shaft, said guard comprising a base plate and a pair of transverse strips carried by said `plate about saidl beater.

6. In a food mixer, the combination of a base plate `having a pair of apertures, with a pair of guard strips, each having its ends secured to said base plate and extending substantially parallel to each other, and a pair of beaters having their lower ends rotatably mounted on said guard strips, and having upper shafts, extending through said apertures in said base plate, said strips being secured transversely to each other at the bottom of said guard, and said strips being formed with feet to support said beaters in erect position.

7. In a portable Afood mixer, the combination" ing a horizontal shaft, a pair of vertical drive shafts carried by the lower side of said casing for driving said beaters, and gearing for connecting said shafts enclosed in said casing.

8. In a portable food mixer, the combination of a guard for supporting a motor, a pair of beaters rotatably mounted in said guard, an electric motor carried by said guard, and provided with a casing of polyhedral form, said motor having a horizontal shaft, a pair of vertical drive shafts carried by the lower side of said-casing for driving said beaters, gearing for connecting said shafts enclosed in said casing, a motor control switch located at the top of said casing, and an actuating knob for said switch rotatably mounted in said top.

9. In a beater unit for household food mixers, the combination of a shaft having an external cylindrical surface and having a bore in its lower end, with mixing elements-comprising a pair of strips of sheet metal. said strips being bent to substantially circular form and having substano tially` axially extending ends, the ends of said strips being located in said bore, and a metal member frictionally engaging in said bore inside said strips and clamping the ends of said strips against the interior of said bore, the circular strips being arranged in intersecting relation with respect toeach other at a point spaced from the end of said shaft.

10. In a beater unit for household food mixers, the combination of a shaft having an external cylindrical surface and having a bore in its lower end, with mixing elements comprising a pair of strips of sheet metal, said strips being bent to substantially circular form and having substantially axially extending ends, the ends of said strips being located in said bore. and a metal member frictionally engaging in said bore inside said strips and clamping the ends of said strips against the interior of said bore, the circular strips being arranged `in intersecting relation with respect to each other ata point spaced from the end of said shaft, said strips having registering apertures at their. intersection and comprising means in said apertures for securing said strips together. v

' ALBERT F. DORMEYER. 

